Inhibitory effect of antiserum to surface antigen P50 of Babesia gibsoni on growth of parasites in severe combined immunodeficiency mice given canine red blood cells

The inhibitory effect of an antiserum to surface protein P50 of Babesia gibsoni on the growth of the parasite was determined with severe combined immunodeficiency mice given canine red blood cells. The antiserum to the recombinant P50 protein significantly inhibited the parasite growth, indicating that P50 might be a useful vaccine candidate.     

Construction and characterization of a fimA mutant of Porphyromonas gingivalis.

Although fimbriae of Porphyromonas gingivalis have been implicated as playing a major role in adherence to gingival tissue surfaces, no conclusive genetic evidence has yet been obtained. The fimA gene, the determinant for the major fimbrial subunit protein, was cloned and sequenced (D. P. Dickinson, M. A. Kubiniec, F. Yoshimura, and R. J. Genco, J. Bacteriol. 170:1658-1665, 1988). We undertook to inactivate the fimA gene by a homologous recombination technique and examined the fimA mutant for changes in surface properties, including production of fimbriae, adherence to human gingival fibroblasts and epithelial cells, hemagglutinating activity, and surface hydrophobicity. To inactivate the fimA gene, we disrupted a fimA clone by insertion of a DNA segment containing an erythromycin resistance (Emr) gene. This was then delivered into P. gingivalis ATCC 33277 from an Escherichia coli K-12 strain, SM10 lambda pir, by using a mobilizable suicide vector, pGP704; recombination at the fimA locus led to the isolation of a fimA mutant. Disruption of the fimA locus and disappearance of FimA production were confirmed by Southern hybridization with a fimA-specific DNA probe and Western immunoblotting with a monoclonal antibody against the FimA protein, respectively. The fimA mutant constructed failed to express long (0.5- to 1.0-micron) fimbriae from the bacterial surface and had a diminished adhesive capacity to tissue-cultured human gingival fibroblasts and epithelial cells. Observation of the bacteria adhering to human gingival fibroblasts by scanning electron microscopy revealed that the wild-type strain had dramatic local changes in the appearance of the microvilli at the point of contact with large bacterial clumps, whereas the fimA mutant did not. In contrast, neither the hemagglutinating activity nor the surface hydrophobicity was changed in the fimA mutant. These data thus constitute the first direct genetic evidence demonstrating that the FimA protein of P. gingivalis is essential for the interaction of the organism with human gingival tissue cells through a function(s) encoded by the fimA gene.     

Anti-arthritic properties of FK506 on collagen-induced arthritis in rats

Objective and design:To determine the effect of FK506 (tacrolimus) on paw inflammation, TNF- expression in joint, and bone and cartilage destruction in type II collagen-induced arthritis (CIA) model in rats.Methods:CIA was induced by immunization of female Lewis rats with an emulsion of bovine type II collagen and incomplete Freunds adjuvant. Paw inflammation was assessed by the increase in paw volume. Tumor necrosis factor (TNF) - expression in hind knee joint was assessed by immunohistochemical analysis. Lesions of bone and cartilage were assessed on the basis of histological change in knee joint, radiographic analysis in hind paw, bone mineral density in femora and proteoglycan contents in the cartilage of femoral heads. FK506 at doses of 1, 1.8 and 3.2 mg/kg or its placebo formulation was orally administered to rats for 28 days from the day after immunization (n = 10). Effect of FK506 was compared with that of vehicle (distilled water).Results:FK506 at a dose of 1.8 mg/kg significantly suppressed paw swelling (p < 0.01) and histological change in knee joint (p < 0.05). Tumor necrosis factor (TNF)- was mainly expressed in the region with a marked infiltration of inflammatory cells in the hind knee joint. FK506 (3.2 mg/kg) markedly reduced TNF- expression. FK506 at a dose of 1.8 mg/kg suppressed radiographic changes in hind paw (p < 0.05) and also recovered the decrease in bone mineral density in the femora (p < 0.05). Proteoglycan contents in the cartilage of femoral heads were determined to evaluate the cartilage destruction more quantitatively and found to significantly decrease in CIA rats. FK506 at a dose of 1.8 mg/kg recovered the loss of proteoglycan contents (p < 0.01).Conclusion:These results show that FK506 is effective in suppressing inflammation, TNF- expression in joint, and damage to bone and cartilage in rat CIA, and may be useful in the treatment of rheumatoid arthritis.     

Three-dimensional two-layer collagen matrix gel culture model for evaluating complex biological functions of monocyte-derived dendritic cells

Dendritic cell-like cells (Mo-DCs) generated from peripheral blood monocytes with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used as tools to treat cancer patients (DC-vaccines). Because Mo-DCs have multiple antigen presentation-related functions, including phagocytosis, migration, cytokine production, and T cell stimulation, establishment of a method for simultaneously evaluating the various functions of Mo-DCs is important. We developed a new in vitro three-dimensional two-layer collagen matrix culture model that consists of a collagen gel containing Mo-DCs as the lower layer and a collagen gel containing necrotic GCTM-1 tumor cells and/or T cells as the upper layer. We used this system to observe simultaneously multiple functions of Mo-DCs by phase-contrast or fluorescence microscopy and to assess IL-12 secretion during more than 2 weeks of culture. We also observed interactions between Mo-DCs and necrotic GCTM-1 or T cells on an individual cell basis by time-lapse videomicroscopy. In addition, we collected Mo-DCs from the collagen gels by collagenase treatment and analyzed the expression of antigen presentation-related molecules such as HLA-DR, CD80, CD83, and CD86 on Mo-DCs. This model may be a useful tool for evaluation of the various functions of Mo-DCs used as DC vaccines and for studies of the complex behaviors of Mo-DCs in vivo.     

Vertical transmission of human T-cell leukemia virus type I (HTLV-I): Detection of proviral DNA in HTLV-I carrier gravida

The seroprevalence rate of human T-cell leukemia virus type I (HTLV-I) in pregnant women in the Osaka district was determined by enzyme-linked immunosorbent assay and Western blot analysis. Twenty-one (1.0%) of 2192 samples tested were positive for both assays and the seropositive parturients were found to be integrated with HTLV-I proviral DNA in their mononuclear cells by a DNA dot blot hybridization assay using HTLV-I DNA probe or by a selective DNA amplification technique using the polymerase chain reaction (PCR). On the other hand, proviral DNA was not detected in cord blood of the neonates born to the carrier mothers, indicating that transplacental infection of HTLV-I during pregnancy could be excluded. The results support the hypothesis that postpartum infection via breast milk plays a significant role among the possible perinatal transmission routes.     

Unique three-way translocation, t(3;14;18)(q27;q32;q21), in follicular lymphoma

A 43-year-old woman was diagnosed as having stage IV follicular lymphoma. Phenotypically, the lymphoma cells were CD5(-), CD10(+), CD19(+), CD20(+), CD23(-), HLA-DR(+), and IgM-lambda(+). Conventional chromosomal analysis showed a three-way t(3;14;18)(q27;q32;q21) in the lymphoma cells, which was confirmed by spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH). Immunohistochemistry revealed that both BCL2 and BCL6 proteins were expressed in the lymphoma cells, whereas only the BCL6 gene, and not the BCL2 gene, was rearranged by Southern blotting. The patient received combination chemotherapy and has been well for 3 years. This is the first reported case showing a three-way translocation involving 2 major lymphoma-specific abnormalities, 3q27 and t(14;18)(q32;q21).     

Mechanisms of blood coagulation induced by latex particles and the roles of blood cells

Latex particles with highly negative or positive charges shortened the clotting time of whole blood and platelet-rich plasma and activated platelet factor 3. Platelet-poor plasma was clotted by the particles with a highly negative charge, but not by those with a positive charge, except hydrophobic particles. Blood coagulation by positively-charged particles was attributed to platelet activation. An enhancement of blood coagulation was also observed in the presence of erythrocytes, leucocytes, their cell membranes or negatively charged phospholipids, and phosphatidylserine instead of platelets. Hydrophilic and low-charged particles suppressed blood coagulation.     

Topical application of FK506 (tacrolimus) ointment inhibits mite antigen-induced dermatitis by local action in NC/Nga mice

BACKGROUND: FK506 ointment (tacrolimus ointment, protopic) is a new drug therapeutically effective for patients with atopic dermatitis (AD). However, the mechanism of action of FK506 ointment on AD is not fully understood. METHODS: We examined the effect of FK506 ointment on mite antigen-induced dermatitis in NC/Nga mice. Clinical symptoms and ear thickness were recorded, and histopathological studies and in vitro analyses were performed. RESULTS: Topical application of FK506 ointment (0.03-0.3%) suppressed the development of dermatitis. In the lesional skin, both interleukin (IL)-4 and interferon (IFN)-gamma were detected, even though the IL-4+/IFN-gamma- T helper 2 (Th2) population was predominant in the regional lymph nodes (LNs). Topical application of FK506 treatment reduced the elevated level of both IL-4 and IFN-gamma in the skin, but did not decrease the expansion of the Th2 population in the LNs. CONCLUSIONS: Topical application of FK506 ointment suppresses dermatitis by inhibiting the activation of inflammatory cells locally, without systemic immune suppression, in this AD model.